Cathode-ray tube



July 22, 1952 F, c, BREEDEN 2,604,599

CATHODE-RAY TUBE Filed Sept. 17, 1949 VINVENTOR.

Frau Ids C Breeder? ATTORNEY Patented July 22, 1952 CATHODE-RAY TUBE Francis 0. Breeden, Bayside, N. Y., assignor to Sylvania Electric Products Inc., a corporation of Massachusetts Application September 17, 1949, Serial No. 116,317

9 Claims. (01. 313-83) The present invention relates to electron ray tubes and more particularly to a novel arrangement of the electron source electrode and beam forming electrodes in cathode ray tubes.

An object of the presentinvention is the provision of a novel-type of cathode ray tube structure. I

Another object of the present invention is the provision 01 a cathode ray tube structure in which the electron beam forming electrodes are of more simplified construction than heretofore known. I

A further object of the present invention is the provision of a cathode ray tube as aforesaid in'which the beam forming and beam producing electrodes are more rigidly held inposition than heretofore.

Still a further object of the present invention is the provision of a cathode ray tube which is more easily constructedthan heretofore known types of cathode ray tubes.

Still another object of the present invention is the provision of a cathode ray tube structure, large portions of which may be prefabricated before assembling into a completed cathode ray tube.

Yet another object of the present invention is the adaptation of disc electrode sealing techniques to cathode raytube construction.

The attainment of these objects in accordance with principles of the present invention result in a cathode ray tube which is particularly usable for television purposes and which requires a smaller focusing coil and a smaller deflection coil than previously known andas a result less horizontal deflection power is used. In accordance with one aspect of, the present invention, the electron stream producing and beam forming electrodes of a cathode ray tube are each held by a numberof flat'metal plates or disc electrodes which are separated by appropriate lengths of coaxially aligned pieces of glass tubing. A glass-to-metal seal is provided attheljunction between each disc electrode and each of the-pieces of the glass tubing. Where it 'is-desired that a pair of adjacent disc electrodes be connected by a metallic or conductingcylindrical electrode portion, it is contemplated that this structure be provided by conductively coating the intervening section'of glass tubing 2 tube may have suitable electrostatic deflecting electrodes mounted therein.

If desired, the neck portion as above described may be welded or fused to the smaller end of a metal conewhich carries on its larger end a glass screen bearing the fluorescent material. The focusing and deflection of. the cathode ray beam in such an arrangement is usually accomplished electromagnetically in which case the electromagnetic focusing. and deflecting coils may be placed about the glass neck portion between the flnal disc electrode and the metal cone. If a metal cone form of construction is used, it is considered preferable that the tube *during the exhaust processes be exhausted through a tubulation in the metal cone since the largest volume of the tube then will be most closely adjacent to theexhaust apparatus and a, better evacuated tube will thus be produced.

It will be apparent that'the electrode construction of a cathode ray tube constructed according to the present invention may be readily and accurately assembled by using the metalto-glass sealing techniques disclosed in prior application, Serial No. 612,029 filed August 22. 1945, now Patent #2,575,448 by Paul Haas, assignor to the assignee of the present application. I

The present invention will be more fully understood by reference to the following detailed description which is accompanied by a drawing in which Fig. 1 illustrates in longitudinal cross section the application of the present invention toa electrostatic deflection type of cathode ray tube while Fig. 2 illustrates a modification of the present invention as applied to a electromagnetic deflection type of cathode ray tube having a metal cone.

Referring now to Fig. 1, there is shown, in this figure, in longitudinal cross-section, a glass cathode ray tube having a bulb portion Iii, having an end wall H coated on its interior with a fluorescent material as indicated by reference number I2. By appropriate proportioning the transverse dimensions of the end vwall bearing the fluorescent screen may be made as large as desired. Only a small screen diameter isshown in the present figurefor the purposes of illustrating the principles of the present invention. The bulb portion I0 is necked down somewhat at its lower open end and in this "portionof the bulb are provided a pair of plates l3. I l for electrostatically deflecting the f beam in one direction and another pair'of plates, one of which is indilargest interior volume of the tube, the air within the tube'may be much more readily exhausted than would be the case if the exhaust took place through a tubulation connected to the smaller end of the tube whereby all the gases within the large volume enclosed by cone 50 would have to pass through all of the small apertures 33, 58, 51 and 55 on their way out of the tube.

Also, the metal seal off tubulation forms a convenient point for connection of a source of potential for positively biasing the cone 50 to the extent desired for accelerating the electron stream after deflection and before it strikes the fluorescent screen I2. While I have particularly shown and described several embodiments of the present invention, it should be distinctly understood that my invention is not limited thereto but that modifications within the scope of the invention may be made.

What I claim is:

1. A cathode ray tube having an envelope with an enlarged body portion and a substantially cylindrical neck portion and a number of electron beam producing and focusing electrodes in the form of discs passing through and supported by said cylindrical neck portion, said electrodes being hermetically sealed to the glass, a pair of adjacent ones of said electrodes being connected together by a conductive coating on the surface of the interposed portion of said cylindrical neck portion, said tube having an exhaust tubulation in the body portion.

2. A cathode ray tube having an envelope with a substantially cylindrical neck portion and a number of electron beam producing and focusing electrodes in the form of discs passing through and supported by said cylindrical neck portion, said electrodes being hermetically sealed to the glass, a pair of adjacent ones of said electrodes being connected together by a conductive coating on the surface on the interposed portion of said cylindrical neck portion.

3. A cathode ray tube having a substantially cylindrical glass neck portion including a number of coaxially arranged sections of glass tubing, adjacent ends of each of said sections of glass tubing being separated by and sealed to disc electrodes, said discs being of greater diameter than the tubing to provide exterior connection surfaces and each having an opening within said neck portion, an end one of said sections of glass tubing having a header sealed to its open end, said header carrying a number of lead in electrodes sealed therethrough, a pair of adjacent ones of said disc electrodes being connected together by a conductive coating on a surface of the interposed section of glass tubing.

4. A cathode ray tube having an electron gun structure including a number of spaced substantially fiat disc electrodes, and interposed coaxially arranged sections of glass tubing, adjacent ends of said sections of glass tubing being hermetically sealed to said disc electrodes, one of said discs carrying a cup shaped cathode having electron emissive material on its end, the connection between said cathode and one disc being so arranged that heat conduction through said disc is minimized.

5. A cathode ray tube having an electron gun n a e structure including a number of spaced substantially fiat disc electrodes, and interposed coaxially'arranged sections of glass tubing, adjacent ends of said sections of glass tubing being hermetically sealed to said disc electrodes, an end one of said electrodes being arranged to carry a cup shaped cathode having an electron emissive material on the outside surface of the bottom ofsa'idcup; V

,6; 'A] cathode ray tube having an electron gun structure including a number of spaced substantially flat disc electrodes, and interposed coaxially arranged sections of glass tubing, adjacent ends of said sections of glass tubing being hermetical- 1y sealed to said disc electrodes, a pair of adjacent ones of said disc electrodes being connected together by a conductive coating on a surface of the interposed section of glass tubing, an end one of said electrodes being arranged to carry a cup shaped cathode having an electron emissive material on the outside surface of the bottom of said cup, a heater element within said cup and connection leads from said heater.

'7. A cathode ray tube having an electron gun structure including a number of spaced substantially flat disc electrodes, and interposed coaxially arranged sections of glass tubing, adjacent ends of said sections of glass tubing being hermetically sealed to said disc electrodes, an end of said electrodes being arranged to carry a cup shaped cathode having an electron emissive material on the bottom of said cup, a heater element within said cup and connection leads from said heater, the one of said glass tubing sections beyond said end electrode being hermetically sealed at its free end and said connection leads passing through said free end.

8. A cathode ray tube having an electron gun structure including a number of spaced substantially fiat disc electrodes and coaxially arranged sections of glass tubing interposed between said disc electrodes, adjacent ends of said sections being hermetically sealed to said disc electrodes, an end one of said electrodes being arranged to carry a cup, shaped cathode; others of said electrodes serving as control grid and anode members, said other electrodes having through apertures within the area surrounded by the seals to said class tubing sections, a pair of adjacent ones of said disc electrodes being connected together by a conductive coating on a surface of the interposed section of glass tubing.

9. A cathode ray tube having an electron gun structure including a number of spaced substantially fiat disc electrodes and coaxially arranged sections of glass tubing interposed between said disc electrodes, adjacent ends of said sections being hermetically sealed to said disc electrodes, an end one of said electrodes being arranged to carry a cup shaped cathode; others of said electrodes serving as control grid and anode members, said other electrodes having through apertures within the area surrounded by the seals to FRANCIS C'. BREEDEN.

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